I would be concerned about random GPS and/or Compass errors with that VTX mounted inside . I probably would have just put a small all-in-one Camera/Tx on top with some Velcro and a small 1s lipo and no need to drill holes but then again I just use litchi and goggles as it already is .
Ive had and still have several fpv racers and while really cool Im not sure I'd do this to my MP.
Its nice not being completely immersed in the MP flying lexperience.